Toddlers learn faster if exposed to diverse objects

A University of Iowa study has suggested that 18-month-olds who played with diversely shaped objects are likely to learn new words twice as fast as those who played with more similar objects.

Outside the lab, one month after the training, tots who had been exposed to the diverse objects were learning an average of nearly 10 new words per week. Kids in the other group were picking up four a week - typical for children that age without any special training.

All of the children given extra training with words figured out that shape was the most important distinguishing feature when learning to name solid objects. This attention to shape, called a 'shape bias,' is not typically seen until later in development.

However, the researchers believed that kids exposed to more variety took the knowledge a step further, also learning when not to attend to shape.

"Knowing where to direct their attention helps them learn words more quickly overall," said lead author Lynn Perry.

"The shape bias enhances vocabulary development because most of the words young kids learn early on are names of categories organized by similarity in shape. And, developing the ability to disregard shape for non-solids helps them learn words like pudding, Jell-O or milk," said Perry.

The study involved 16 children who knew about 17 object names when the study began. Half of the kids were taught names of objects by playing with groups of toys that were nearly identical; the other half used toys that differed significantly - for example, a small, cloth, jack-o-lantern bucket; a trash bucket with no handle; and a traditional plastic bucket.

When tested on unfamiliar objects that fit into the categories they'd been taught - such as a bucket they'd never seen before - kids in the variable group performed better.

"We believe the variable training gave them a better idea of what a bucket was. They discovered that the buckets were all alike in general shape, but that having a handle or being a particular texture didn't matter," said Perry.

In additional tests, researchers looked at whether the tots learned names of new objects by focusing on substance or shape.